Medical science has tried repeatedly to pinpoint the
etiology, and many hypotheses were made, such as: •
Asperger's syndrome (now known as
autism spectrum disorder) or other
pervasive developmental disorder •
Chagas disease •
Chronic fatigue syndrome •
Crohn's disease •
Cyclic vomiting syndrome •
Lactose intolerance •
Lupus erythematosus •
Mast cell activation syndrome •
Ménière's disease •
Orthostatic intolerance •
Panic disorder with
agoraphobia •
Obsessive–compulsive disorder •
Postural orthostatic tachycardia syndrome •
Posttraumatic stress disorder •
Psychosomatic disease •
Tick-borne disease Diagnoses for Darwin's illness have been uncritically reviewed from a chronological aspect with emphasis on the variety of these diagnoses. More recently, there has been a critical review with emphasis on the maternal (Wedgwood) family history as an indicator of the nature of the illness.
Psychic causation Darwin found that his illness often followed
stressful situations, such as the excitement of attending a meeting. Having escaped "smoky dirty London" to his country retreat of the former parsonage of
Down House at
Downe, he became increasingly reclusive, actually fitting a mirror outside the house, so that he could withdraw when visitors were coming around the corner. When he left, it was mostly to visit friends or relatives, though he did endeavour to meet his obligations to attend scientific meetings.
Diagnosis of panic disorder and agoraphobia Barloon and Noyes report that as a young man, Darwin had "episodes of abdominal distress, especially in
stressful situations". He had a "premorbid vulnerability" which was referred to as "sensitivity to stress of criticism in his youth". They contend that "variable intensity of symptoms and chronic, prolonged course without physical deterioration also indicate that his illness was psychiatric." Panic disorder usually appears in the teens or in early adulthood with an association with potentially stressful life transitions. The histories of panic disorder patients often include some type of separation from a person who is emotionally important to them, which may be significant as Darwin's mother died in 1817 when he was eight, though apparently Darwin had a happy childhood overall and was encouraged by his siblings. Bowlby suggested that
separation anxiety may help cause the development of panic disorder in adulthood and that agoraphobic patients frequently describe parents as dominant, controlling, critical, frightening, rejecting, or overprotective, which matches (disputed) descriptions of Darwin's father as tyrannical (see below). A study by Chambless and Mason says that regardless of gender, the less masculine in trait a person afflicted with panic disorder is, the more likely they are to use avoidance (social withdrawal) as a coping mechanism. Individuals who have more masculine traits often turn to external
coping strategies (for example,
alcohol). Bean wrote that while Darwin had great confidence, at the same time he was
neurotic, became nervous when his routine was altered, and was upset by a holiday, trip, or unexpected visitor. Colp disputes a diagnosis of agoraphobia, because Darwin dutifully attended 16 meetings of the Council of the
Royal Society and was away from home about 2,000 days between 1842 and his death in 1882. However, Barloon and Noyes state that Darwin only left home infrequently, usually accompanied by his wife. They cite Darwin declining an invitation: "I have long found it impossible to visit anywhere; the novelty and excitement would annihilate me."
Relationship with father Kempf imputes a psychic cause based on the theory of
Oedipal complex, proposing that Darwin's illness was "an expression of
repressed anger toward his father" (the
physician Robert Darwin). Kempf believed that Darwin's "complete submission" to a tyrannical father prevented Darwin from expressing
anger towards his father and then subsequently toward others. In a similar diagnosis, English psychiatrist Dr. Rankine Good stated, "Thus, if Darwin did not slay his father in the flesh, then he certainly slew the Heavenly Father in the realm of natural history," suffering for his "unconscious
patricide" which accounted for "almost forty years of severe and crippling neurotic suffering." Sir Gavin de Beer disputed this explanation, claiming a physical causation. Darwin's autobiography says of his father, "... [he] was a little unjust to me when I was young, but afterwards I am thankful to think that I became a prime favourite with him." Bradbury quotes J. Huxley and H.B.D. Kettlew: "The predisposing cause of any psychoneurosis which Charles Darwin displayed seems to have been the
conflict and
emotional tension springing from his ambivalent relations with his father ... whom he both revered and subconsciously resented." Bradbury also quotes John Chancellor's analysis: "... [Darwin's] obsessive desire to work and achieve something was prompted by hatred and resentment of his father, who had called him an idler and good-for-nothing during his youth." Such
psychoanalysis remains controversial, particularly when based only on writings.
Relationship with wife, nervousness about being left alone Peter Brent writes in his biography of Darwin,
Darwin: A Man of Enlarged Curiosity, that Charles and
Emma Darwin's "ties to each other were linked to childhood and the very beginnings of memory. They had a common history, a joint tradition. It is hard to think their relationship a passionate one, but it was happy, and the happiness had deep roots." Bradbury—himself a social psychologist—draws on this biography to argue that in Darwin's letters, Emma was "always the mother, never the child, Darwin always the child, never the father." Darwin gave his wife the nickname "mammy", writing, "My dearest old Mammy ... Without you, when sick I feel most desolate ... Oh Mammy, I do long to be with you and under your protection for then I feel safe." Brent states that it is difficult to see that this is a thirty-nine-year-old man writing to his wife and not a young child writing to his mother. Barloon and Noyes quote Darwin's admission to Dr. Chapman of "nervousness when Emma leaves me", which they interpret as a fear of being alone associated with his panic disorder. Like his mother, Darwin's wife Emma was devoutly
Unitarian. His father, speaking from experience, warned Charles before he proposed to Emma that "some women suffered miserably by doubting about the salvation of their husbands, thus making them likewise to suffer." Darwin did tell Emma of his ideas at that stage, and, while she was deeply concerned about the danger to his afterlife expressed in the
Gospel, "If a man abide not in me...they are burned", she married him and remained fully supportive of his work throughout their marriage. She read and helped with his "Essay" setting out his theory in 1844, long before he showed his theory to anyone else. She went through the pages, making notes in the margins pointing out unclear passages and showing where she disagreed. As his illness progressed, she nursed him, restraining him from overworking and making him take holiday breaks, always helping him to continue with his work.
Religious tension Darwin had a complex relationship to religion. The
Darwin–Wedgwood family were of the Unitarian church, with his grandfather
Erasmus Darwin and father taking this to the extent of
Freethought, but, in the repressive climate of the early 19th century, his father complied with the
Anglican Church of England.
Charles Darwin's education at school was Anglican, then after in
Edinburgh, he joined student societies where his tutors espoused
Lamarckian materialism. He liked the thought of becoming a country clergyman, and before studying at the
University of Cambridge, "as I did not then in the least doubt the strict and literal truth of every word in the Bible, I soon persuaded myself that our Creed must be fully accepted." The clergyman naturalist professors there who became his lifelong friends fully accepted an ancient earth but opposed
evolutionism which they felt would undermine the social order. He did well at theology and, in his finals, came 10th out of a pass list of 178. At both universities, he saw how evolution was associated with
radicals and democrats seeking to overthrow society and how publicly supporting such ideas could lead to destruction of reputation, loss of position and even imprisonment for blasphemy. At Cambridge, he was convinced by
William Paley's writings of
design by a Creator, but, on
the Beagle expedition, his findings contradicted Paley's beneficent view. On his return, his deepening speculations led to the
inception of Darwin's theory, and he increasingly disbelieved in the Bible, gradually becoming what was later termed an
agnostic. Darwin was clearly worried by the implications of his ideas and desperate to avoid distress to his naturalist friends and to his wife. When first telling his friends, he wrote "it is like confessing a murder", and his writings at the time of the
publication of Darwin's theory suggest emotional turmoil. What is unclear is whether this was anxiety about disgrace and damage to his friends, or about his loss of faith in Christianity, or indeed a rational fear of the harsh treatment he had seen meted out to radicals and proponents of evolutionism.
The Chagas hypothesis Advanced for the first in time in 1959 by eminent
Israeli specialist in
tropical medicine Dr.
Saul Adler from
Hebrew University, the hypothesis of
Chagas disease was based partly on the fact that during
the Beagle expedition, Darwin was bitten by the
insect vector of this disease near
Mendoza to the east of the
Argentinian Andes while on one of his land exploration trips. He noted in his journal for 26 March 1835: At night I experienced an attack, & it deserves no less a name, of the Benchuca, the great black bug of the Pampas. It is most disgusting to feel soft wingless insects, about an inch long, crawling over ones body; before sucking they are quite thin, but afterwards round & bloated with blood, & in this state they are easily squashed. The great black bug of the
Pampas is identified by
Richard Keynes as
Triatoma infestans, commonly called
winchuka (vinchuca), one of the
triatomine vectors for
Trypanosoma cruzi which leads to Chagas disease. It is unlikely that Darwin was infected on this occasion as he did not mention having a fever in the days following the incident, Modelling of triatomine geographical distribution in Chile shows that Darwin traveled extensively in the areas of central and northern Chile where these bugs occur, sleeping outdoors and in rural houses. His paper on the topic was accepted by the
BMJ and the
Medical Journal of Australia, and was published in December 2009. In a supplement published in February 2012, he proposed that stroke-like episodes of memory loss and partial paralysis which do not occur with CVS are characteristic of the
MELAS syndrome. An A3243G mtDNA mutation has been found in 80% of patients with this syndrome, and has also been described in those with CVS. This mutation in
mitochondria is associated with symptoms of intestinal problems, seasickness and Ménière's disease as well as CVS and MELAS syndrome, thus giving a shared source of the various problems that affected Darwin. Any
mitochondrial disease would have been inherited from his mother
Susannah Darwin, whose own mother had 8 other children. Some of them had illnesses which could have been related to the same mutation. CVS was also proposed as part of the cause in a 2011 analysis by gastroenterologist Sidney Cohen of the medical college of
Thomas Jefferson University in Philadelphia. His study explained the illness as being due to a combination of cyclic vomiting syndrome, Chagas disease, and
Helicobacter pylori.
Other possible causes Evidence for familial systemic
lactose intolerance syndrome was that vomiting and gastrointestinal symptoms usually appeared two to three hours after meals and that, apparently, Darwin got better when he stopped taking
milk or
cream.
Combined causes From a clinical point of view, perhaps Darwin suffered from more than one disease, and had many psychosomatic complications and phobias arising from his debilitating condition. This is known to happen with many patients today, such as in severe cases of panic disorder, usually accompanied by hypochondria and depression. Dr.
Peter Medawar has supported the diagnosis that Darwin's health problems were part organic, part psychological. Colp concluded that Darwin's illness consisted most probably of panic disorder without agoraphobia, psychosomatic skin disorder, and possibly Chagas disease of the stomach, which he suggested "was first active and then became inactive, permanently injuring the parasympathetic nerves of his stomach and making it more sensitive to sympathetic stimulation and hence more sensitive to the psychosomatic impact of his anxieties. An organic impairment best explains the lifelong chronicity of many of his abdominal complaints." Thus, the psychological aspects of Darwin's illness might be both a cause and an effect of Darwin's illness. D.A.B. Young wrote in a Royal Society journal in 1997 that the psychogenic view of Darwin's sickness "holds the field". The proponent of Chagas disease, Dr. Saul Adler, stated that Darwin may have suffered both from Chagas disease and from "an innate or acquired neurosis". At a conference hosted by the
University of Maryland, Baltimore, School of Medicine on the topic of Darwin's ailments, gastroenterologist Dr. Sidney Cohen of
Thomas Jefferson University concluded that in his early years Darwin had suffered
cyclic vomiting syndrome, but as he had brought up secretions such as stomach acid rather than food, this had not affected his weight and nutrition. He believed that
Chagas disease contracted during the
Beagle voyage was consistent with Darwin's account of his fever at that time and his later gastrointestinal complaints, as well as the heart disease later in life that led to Darwin's death. In addition,
Helicobacter pylori which often occurs with Chagas would have caused Darwin to have peptic ulcer disease. ==Hereditary disease==